The present invention refers to a snap action switch.
During slow operation of an ordinary toggle switch, as is for instance the case for its use in a temperature regulator, a condition occurs before the disconnection of two touching contacts, where almost no more contact pressure exists. This leads to an increased transfer resistance which changes by order of magnitude accompanied by vibration sensitivity and eventual spark formation.
For those mode of application it is known--according to the DE-AS No. 26 19 837 for instance, to use a dual snap function and therefor construct the toggle switch in such a way that a toggle control action is started before the contact pressure sinks to zero. There are many such suggestions for solution, which, however, necessitate an increased operational path for a control tolerance at the control plunger and/or a relatively extensive manufacturing cost.
In U.S. Pat. No. 2,495,349 to Rohr a toggle switch is described the task of which is always to keep connected electrically one of two switch-current paths with the switch-feed line. This means that the current interruption which happens in a common switch during the flying time of its mobile contact needle, does not occur.
To solve this problem, Rohr uses two toggle springs 34, 36 lying one above the other, one of which must have an additional stamping 51. Thus, there are not two identically same toggle springs and their timely shifted toggle processes are only triggered when the contact pressure of the mobile contact needles has sunk to zero. The switch processes of the individual contact springs 34, 36 show no double toggling. Therefore, in view of the subject matter of the present application, the task of which is to create a snap action switch with dual snap action, the Rohr patent is not related.
The patents to Busser CH-PS No. 366 317 and Spahn De-AS No. 2619 837 describe two different arrangements of toggle switches with double toggling which necessitates beside the toggle spring a further spring needle and an additional buffer.
The subject matter of the present application also has an additional buffer, but its construction compared to what has been known necessitates a much smaller input.